Coin dimple punch



April 30, 1 R. J. GARGRAVE 2,790,477

COIN DIMPLE PUNCH Filed Aug. 6, 1952 FIG. I

1-743 Fla 4 as m 5 A FIG. 6

3nnentor KOBfRI' J 6426K!) l/E orucg United States Patent COIN DIMPLE PUNCH Robert. J. Gargrave, Dayton, Ohio, assignor to Dayton Perforators Inc., Dayton, Ohio, a corporation of Ohio Application August 6, 1952, Serial No. 302,974

3 Claims. (Cl. 153-21) This invention relates to punch devices, and more particularly to a coin dimple punch as used in the countersinking of rivet holes in sheet metal.

Devices of the class described have customarily taken the form of a one-piece cylindrical body having a pro jecting pilot portion at one end and a forming shoulder at the base of such portion. While the devices are made of hardened, treated metal, frequent breakage occurs at the pilot portion, necessitating the discarding of the entire device.

The object of the invention is to simplify the construction as well as the means and mode of operation of coin dimpling punches, whereby such punches may not only be economically manufactured but will be more efficient and satisfactory in use, adaptable to interchange of punch inserts, having a longer useful life and be unlikely to get out of repair.

A further object of the invention is to reduce the initial cost of the punch device and provide an inexpensive means of renewing the useful life thereof.

Another object of the invention is to make the punch device a fabricated unit in which the pilot portion and forming shoulder are a part of a separable and individually replaceable insert member.

A further object of the invention is to provide a separable insert member as described which is adaptable in its construction to different types of punch bodies.

Still another object of the invention is to provide a structure making possible the building of added size and strength into the forming shoulder.

A still further object of the invention is to provide a tapered seat for the insert member in the punch body, such seat serving to absorb some of the endwise thrust exerted on the insert member and to efiect under use a substantially gripping engagement between the insert member and body.

A still further object of the invention is to provide alternative means for easily removing a broken or worn insert member from the body.

A further object of the invention is to provide a coin dimpling punch possessing the advantageous structural features, the inherent meritorious characteristics and the particular construction herein disclosed.

With the above primary and other incidental objects in view as will more fully appear in the specification, the invention intended to be protected by Letters Patent consists of the features of construction, the parts and combinations thereof, and the mode of operation, as hereinafter described or illustrated in the accompanying drawings, or their equivalents.

Referring to the accompanying drawing, wherein is found the preferred but obviously not necessarily the only form of embodiment of the invention,

Fig. 1 is a view in longitudinal section of a coin dimple punch in accordance with a first illustrated embodiment of the invention;

Fig. 2 is a fragmentary view in longitudinal section 2,796,477 Patented 30, 1957 "ice showing a modified construction of insert member and punch body;

Fig. 3vis a view like Fig. 2 showing another form of cooperation between the insert member and punch body;

Fig. 4 is a view like Figs 2 and 3, showing still another form of cooperation between the insert member and punch body;

Fig. 5 is a view in side elevation of a punch assembly like that of Fig. 1, but showing an alternative means for dislodging a worn or broken insert member.

Fig. 6 is an end view of a punch showing the relationship between the body, forming shoulder and pilot point.

Like parts are indicated by similar characters. of reference throughout the several views.

Referring to the drawings, a coin dimple punch in accordance with the embodiment of the invention shown in Fig. 1 comprises a cylindrical body portion or holder 10. From one end of the body 10 projects a reduced diameter portion 11 constructed and arranged to be received in suitable holding means, for example a pneumatic hammer, squeeze press or similar equipment. Opening through the opposite end of the body 10 is a bored out recess 12 mounting an insert 13. Such insert has a shank portion 14 received in the recess 12, a projecting pilot portion 15, and, at the base of the portion 15, an annular formingvshoulder 16. The pilot portion 15 has a arcuate contour to facilitate its entry into an opening in the work. The outer face of the shoulder 16 has a sloping formation to effect the actual dimpling operation, in response to an approaching motion of the punch toward the work, and in conjunction with appropriate backing or anvil means.

The insert 13 with its shoulder 16 is so formed that it will complement and fit the adjacent end of body 10, with which the shoulder 16 has intimate contacting relation. The end surfaceon the body 10 is flat, or perpendicular with respect to the longitudinal axis of the punch, in the embodiment of Fig. 1, while as shown in Fig. 2, the end surface of body 17 is concave and in Fig. 3, the end surface of body 19 is convex. Ineach form it will be seen that the insert 13 with its shoulder 16 is complementary to and merges with the end surface conformation of the holding body.

In Fig. 4 another cooperative arrangement between forming shoulder and punch body is illustrated. According to this construction-and ararngement of parts,'a body 22 has a tapered longitudinal recess 23 in the outer end of which is a cylindrical counterbore 24. An insert member 25 is mounted in the recess 23 and has a forming shoulder 26 which occupies a seat in the counterbore 24. By reason of the counterbore 24, the shoulder 26 can be made relatively long and heavy, thus reducing the likelihood of breakage.

As indicated, the shank 14 of insert 13, and the shank of the corresponding members in the other views, is formed with a taper, the recesses 12 and 23 having a complementary taper. Such taper is of a sticking type which materially assists in retaining the insert in place in the supporting bodies. In many instances the sticking taper affords suflicient holding without the use of other supplemental locking means. Firmly seated in the tapered recess 12, the insert 13 in effect becomes wedged therein, resisting motion of the insert out of the recess. Moreover, the seating of the tapered insert member in the tapered recess eliminates any possibility of the shoulder 16 being subjected to excessive strain caused by pressure of the insert against the work inasmuch as the shoulder 16 does not have direct bearing upon the end face of the holding body 10.

In the installed position of the insert, the end of shank 14 lies substantially in line with a series of radial openings 28 in the punch body. The openings 28 provide for c s f a wa s zrh ped 29 I9 thereses 12 h r it may act as a cam on the end of the shank to dislodge the insert member from its .seat in the recess. It will be understood that this is a feature connected with the operation of removing an insert member that has become W n. o which has mken, s th t m b replaced by a new insert thereby in effect renewing the life of the punch.

As a supplemental means for retaining the insert in the punch body, a set screw 31 may be used which is adjustable in a radial bore 32 into and out of locking engagement with the insert.

Fig. 5 discloses an alternative means for dislodging or removing a worn or broken insert member. Thus, ac-

cording to this construction, a punch body 33 presents a recess 34 mounting an insert 35, and further presents a small diameter bore 36 which extends longitudinally from the opposite end of the punch body, through the extension 11, to the inner end of recess 34. Any form of elongated pin or screw device 37 can be passed through the fabricated assembly. Thus the insert can be made of a hard, treated material and yet be relatively inexpensive because of its small size. The body portion 10, which makes up the principal bulk of the punch may be made of a less expensive, conventional metal. 7

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages.

While in order to comply with the statute the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise but one of several modes of putting the invention into effect.

Having thus described my invention, I claim;

arooavr l. A coin dimple punch, including a body member having opposed ends, one end thereof being constructed and arranged to be received in suitable holding means, a recess in the other end of said body having a longitudinally tapering formation, said other end having an end surface approximately at right angles to the longitudinal axis of said body member ,through which surface said recess opens, an insert received insaid recess, a projecting pilot portion on said insert, and an annular forming shoulder on the base of said pilot portion saidforming shoulder presenting a frusto conical wall having its base in closing relation to said recess and in merging continuing relation to the said end surface of the said other end of said body member.

2. A punch according to claim], characterized in that the said end surface of the said other end of said body having said recess is of arcuate formation.

3. A coin dimple punch, including a body member having opposed ends, one end thereof being constructed and arranged to be received in suitable holding means, a recess in the other end of said body having a longitudinally tapering formation, said other end of the body having an end surface approximately at right angles to the longitudinal axis of said body member through which said recess opens, an insert received in said recess and having a shank portion eomplernentarily tapered to seat in said recess, a projecting pilot portion on said insert, an annular forming shoulder on the base of said pilot portion, said forming shoulder presenting a frusto conical wall having its base in closing relation to said recess and in merging continuing relation to the said surface of said other end of the body member, supplemental means for retaining the insert in the recess, and manually op erable means for removing the insert from said recess.

References Cited in the file of this patent UNITED STATES PATENTS 256,078 Titus Apr. 4, 1882 701,077 McKinney May 27, 1902 894,250 Woods July 28, 1908 1,304,954 Foster May 27, 1919 1,411,335 Foote Apr. 4, 1922 2,167,014 Verderber July 25, 1939 2,288,378 Veit June 30, 1942 2,317,791 Miller Apr. 27, 1943 2,374,019 Kahler et al Apr. 17, 1945 2,397,382 Smith Mar. 26, 1946 2,449,247 Pancek Sept. 14, 1948 

